Conventionally, the choosing of fonts used in an electronic document is entrusted to the person producing such a document. Fonts installed in electronic document processing equipment such as word processors, etc. differ from machine to machine, and such machines are usually limited to only being able to handle a specific language. Producers of documents who wish to produce a document containing a number of languages or who wish to use characters not included on a basic font set, therefore, have to define the font for such characters as external characters in order to use such fonts in an electronic document. This is not much a problem during the exchange of documents printed on paper but has become a major drawback with the proliferation of exchanging electronic documents over the internet and during registration of electronic documents in electronic libraries.
Producers and readers of electronic documents have to have the same font sets and character codes in order to reliably exchange character information. However, considering the current situation in which the font sets that can be used on each platform are different, in formats used in exchange of information such as formats passed over internet lines and formats for data stored in centralized files within an electronic library or within a company, standardization of standard fonts used for character information is necessary.
Font replacement has been possible in related electronic document production systems but in this replacement, the character code information is saved as is and just the font information is replaced with another font. For example, external character fonts are usually defined as independent fonts, with it then being usual to decide an index of characters from the order of definition of the characters. Font replacement cannot, therefore, be carried out even when large font sets such as, for example, the Unicode font which includes all of the principle characters from around the world (including the JIS supplementary kanji set spanning several thousand words that are not supported by usual electronic document production systems), are used because the character indexes within the fonts (character coding) are different.
A user would need to manually change code values for character code within an electronic document when replacing fonts. In order to achieve this, the user would need to know the font index used in the original electronic document and the index of the characters corresponding to the characters to be replaced. When electronic documents are accumulated in an electronic library, the number of producers of accumulating documents is an ever-increasing large number. Due to the storage of font sets used in all of the documents, and the storage of the indexes of the characters within the font sets, manual standardization of the documents one at a time is practically impossible.
As a result, with electronic libraries handling character information of electronic documents and centralized files within companies in the related art, the only option has been to accumulate documents as they are made, with attempts at standardization of electronic documents being basically abandoned. Unintelligible characters therefore occur because of the differences between the font environments of producers and users of the electronic documents. This causes inconvenience when exchanging an electronic document and means that displaying and processing of electronic documents made by other systems cannot be carried out by systems limited to Tier-O resources, etc. In Japanese Patent Laid-open Publication No. Hei. 7-319854, there is disclosed an external character management system for making and distributing external character font files in an effective manner. However, this technology is for managing external fonts in closed network environments and cannot be applied as is to the standardization of character information in electronic documents that is the object of the present invention.